1. Field of the Invention
The present invention relates to the field of capacitor design and fabrication.
2. Prior Art
A number of problems exist in state-of-the-art capacitors. Capacitors are generally inexpensive, causing manufacturers to eliminate leading edge technology as too costly for these products. Instead, manufacturers tend to move toward finding dielectrics with higher dielectric constants to enhance the capacitance per unit area. This leads to compromises in other parameters, such as dielectric strength, uniformity of layers, reliability, stability, degradation of materials and ultimately to increased capacitor volume, thereby compromising the capacitance per unit volume.
Capacitors have been made by sandwiching a layer of dielectric 20 between two conductive layers 22 on a substrate 24, as shown in FIG. 1. This allows only one plate, and therefore provides a relatively low capacitance. Attempts have been made in the prior art to achieve higher capacitances by stacking multiple layers (FIG. 2), but this still does not reach the capacitance per unit area of the present invention.
The prior art devices tend to use a dielectric material that is on the order of several thousandths of an inch thick, in comparison to the present invention which has dielectric thicknesses which are significantly less than 1 micron (1 thousandth of an inch=25 microns). Also the prior art devices generally use a high dielectric constant material such as Barium Titanate. However these materials have low dielectric strengths and substantial variations of properties with temperature and age. They thus give lower voltage results and poor reliability.